Backspacing mechanism for typewriters



April 24, 1928.

O. A. HOKANSON BACKSPACING MECHANISM FOR TYPEWRITERS Filed Ju] y 29 l925 Jim/EN 70,

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Patented Apr. 24, 1928.

UNITED]STATES-FPATE-NT oFrlcrz.

OTTO A. HOKANSON, OF WOODSTOCK, ILLINOIS, ASSIGNOR TO WOODSTOCK TYPE- WRITER COMPANY, OF WOODSTOCK, ILLINOIS, .A. CORPORATION OF ILLINOIS.

BACKSPAGING MECHANISM FOR TYPEWRITERS. 7

Application filed J'uly 29,1925. Serial No. 43,747.

This invention relates .to mechanism for moving the platen carriage of a typewriter backwardly, step by step, and has foruts object the provision of such mechanism which shall be of improved construction and operation and which is electro-magnetmally operated.

The invention is simplified in the combi-' nation and arrangement of parts shown in the accompanying drawings anddescribed in the following specification, and it is more particularly pointed out in the appended' I v I ,85 and operated by a contact lug 36 on claims. V

In the drawings, Fig. 1 is a fragmentary rear view of a portion of a typewriter, showing one embodiment of the present invention applied thereto. 2

Fig. 2 is a key operated switch for controlling the mechanism illustrated in Fig. 1.

As illustrated in the drawings, the numeral 10 designates the frame of a typewriter provided with the usual platen carriage and type bars. The platen carriage is providedv with the usual or any approved escapement mechanism which cooperates with'a rack 11,

for controlling the movement of the platen:

transversely of the typewriter frame. A backspace lever 12 is pivotally mounted at 13 on a bracket 14 extending downwardly from the top plate 15 ot' the typewriter frame. A pair of toggle levers16 and 17 are pivotally connected at 18 and the pivotal connection 18 is attached. to a plunger 19 by means of a link 20. The plunger 19 operates in a solenoid 21, supported on a bracket 22 attached to vthe frame 10 by screws 23. The lower end otthetoggle link 16 is pivoted at 24'to the bracket 23 and the upper link 17 is pivoted at 25 to'the lever 12.

hen thesolenoid 21 is energized by a current in the conductors 26 the plunger 19 willbe drawn into the solenoid and the toggle lever will swing the backspaceclever 12 on its pivot 13 in a counterclockwise direction, as viewed in Fig. 1. 5

The upper branch'26 of the lever 12 carries a pawl 27, which project's througha slot 28 in the top plate 15 in position to; engage the rack 11. spring 29 tends to rotate the pawl 27 upon its pivot 30 into engagement with the teeth of the rack 11,

but when the lever 12' is in the position I lever,

ever the solenoid 21 isdeenergized.

' The circuit for the solenoid 21 is controlled bya backspace key 82 whichoperates a switch 33 for closing the circuit, in the conductors 26.

A switch blade 34 is pivotally mounted at the lever 37'controlled by the key 32. A

spring 38 normally opens the, switch when the key is released. I

Itwill be apparent, that operation'of the back space key 32 will energize the solenoid 21 and cause back letter space movement of the rack 11. When the key is released, the dog 27 will be returned to 'positio'nto again engage the rack 11 on the-next depression a of the key. I

The only effort on the part of the operator is that required to depress the key lever v 37,.since thc energy for moving the platen backwardin opposition to the platen carrlage spring rent" in the circuit 26.

is supplied by the electric cur-- '1-."In a-typewriter a backspace lever, a a

solenoid, a plunger arrangedto be operated by said solenoid and toggle mechanism for connecting said plunger with said lever."

2. The combination with a'typewriter hav-' ing a rear frame member and a platen carriage rack, of back space lever; for moving said rack, a solenoid mounted on said rear, frame'member andhaving its axis ex- 7 tending in the direction ofthe plane of said rear frame-member, a plunger arranged to be operated by said solenoid, toggle links mounted on: said rear frame member and connecting said plunger with said backspace an electric circuit for supplying energy to said solenold, a sw tch for closingsaid circuit and a key for operating said.

switch. I p

In testimony whereof I have signed my 'name to this specification on this 24th day of July, A. D. 1925.

OTTO A." HOKANSON. I 

